It is generally recognized that success in the marketplace, particularly with respect to fluid-absorbing articles such as disposable diapers, incontinence garments or pads and the like, depends substantially on functional efficiency, including comfort of the wearer, appearance, and price of the product being sold.
In general, such product must have an efficient fluid-retaining core component, usually comprising one or more layers of absorbent material such as wood pulp, rayon, gauze, tissue or the like, and, in some cases, superabsorbent particulate matter or powder (SAP).
To protect clothing, and surrounding areas from being wetted and stained by fluids retained in a pad or core component, such ,articles are generally backed by a fluid-impervious backing component and also usually possess a nonwoven-type fabric or coverstock material, which defines, at least, the body-contacting surface of the fluid-absorbing article. Functionally speaking, the nonwoven coverstock material, along with optional intermediate acquisition layers of defined porosity are relied on to control fluid flow and insulate the wearer from continuous contact with moisture already retained in the pad or core. The facing or coverstock must be pervious to fluids on its body-contacting side to promote rapid transfer of each fluid acquisition or insult directly into the fluid absorbent core component while, itself, remaining soft, dry and essentially nonabsorbent to aqueous fluids.
Prior art, as exemplified by Rodwanski et al. (U.S. Pat. No. 4,767,586), for instance, obtains disposable diapers from nonwoven webs of cellulosic fiber using superimposed layers of material in selected areas. This reference also proposes that webs of cellulosic fiber (i.e. for paper making) may be used in different fiber compositional areas.
U.S. Pat. No. 2,751,962 relates to a system for producing fibrous products in which coarse and fine denier fiber are incorporated into an integral web.
Marshall et at. (U.S. Pat. No. 4,931,357), relates to fibrous material from webs formed of different staple mixtures fed through separate lickerins feedably arranged in parallel axial relation over a conveyor screen or belt, the fiber feed is oriented on the belt by use of baffles to define separate lateral and vertical fiber cross-sections within the resulting web. The web, as shown, is folded over to form a cylindrical-shaped component having a homogeneous external layer.
It is now recognized that additional improvements can be achieved regarding the comfort of the wearer of such articles (a) by increasing the overall efficiency and liquid acquisition rate of the core component itself and (b) by improving fluid flow control, especially back flow or rewet properties, by varying the make up of core and/or coversheet components.
It is an object of the present invention to obtain a fluid-absorbent core component of increased receptivity and storage efficiency, plus reduced rewet characteristics.
It is a further object to obtain a core component capable of avoiding local areas of over saturation.